1. Field of the Invention
The present invention relates to a data processing apparatus, a data processing method, and a program. More particularly, the present invention relates to a data processing apparatus capable of, for example, effectively removing mosquito noise from image data, to a data processing method for use with the data processing apparatus, and to a program for use with the data processing method.
2. Description of the Related Art
An encoder that compresses image data by using a compression method, such as based on the MPEG (Moving Picture Experts Group) format for compressing image data, divides image data into blocks, and performs a DCT (Discrete Cosine Transform) process on each block. For this reason, when a decoder decodes image data encoded using an MPEG system, theoretically, mosquito noise can be present around edges of images of the decoded image data.
In general, a noise removal apparatus of the related art for removing mosquito noise detects changes in pixel values of image data and determines that the pixel values correspond to the edge if the changes in pixel values are large. Then, the noise removal apparatus filters the edges of images of the image data so that the degree of smoothing thereof becomes higher than that of filtering with respect to portions other than the edges. As a result, mosquito noise that occurs around the edges of images of the image data is removed.
An apparatus for improving contrast of images by using a non-linear smoothing filter for amplifying image data in portions other than edges while maintaining edges whose changes in pixel values are high has been disclosed (refer to, for example, Japanese Unexamined Patent Application Publication No. 2001-298621).